Organic matter degradation and arsenic enrichment in different floodplain aquifer systems along the middle reaches of Yangtze River: A thermodynamic analysis

Activated Carbon Application Simultaneously Alleviates Paddy Soil Arsenic Mobilization and Carbon Emission by Decreasing Porewater Dissolved Organic Matter

“…28,29 Besides, DOM biodegradable components can serve as a microbial carbon source for anaerobic respiration. 30 Multiple studies have reported that the biodegradable DOM links to As mobility in geogenic Ascontaminated groundwater, 31,32 governing CH 4 emission in rivers and lakes. 33−35 However, the function of DOM as an electron shuttle in fueling As release and CH 4 emission has been only proposed but not investigated experimentally.…”

“…Dissolved organic matter (DOM) is a representative electron shuttle for microbial Fe­(III) reduction. , Besides, DOM biodegradable components can serve as a microbial carbon source for anaerobic respiration . Multiple studies have reported that the biodegradable DOM links to As mobility in geogenic As-contaminated groundwater, , governing CH 4 emission in rivers and lakes. − However, the function of DOM as an electron shuttle in fueling As release and CH 4 emission has been only proposed but not investigated experimentally. , Therefore, the critical electron shuttling function of DOM in controlling soil Fe­(III) reduction and potentially regulating As fate and GHG emission needs to be systematically explored.…”

Unraveling the Coupled Dynamics between DOM Transformation and Arsenic Mobilization in Aquifer Systems during Microbial Sulfate Reduction: Evidence from Sediment Incubation Experiment

“…In organic-matter-rich aquifer systems, dissolved organic matter (DOM) plays an essential role in fueling versatile microbial metabolic activities [15], and these microbially mediated transformations in minerals and aqueous chemical components could subsequently regulate the groundwater As concentrations. Recent studies highlighted several critical aspects involved with DOM functioning and As mobilization in groundwater systems: (1) Bioavailable DOM could fuel the reductive dissolution of arsenic-bearing iron (hydr)oxides or the microbial sulfate reduction, subsequently influencing the mobilization or incorporation of arsenic [16]; (2) Humic components in the DOM could form ternary complexes with Fe and As, enhancing the stability of As in the aqueous phase [17]; (3) Some particular humic components could serve as electron shuttles due to their redox-active quinone moieties, expediting the biogeochemical processes accounting for As mobilization in groundwater [18]; (4) Humic substances could also compete for active surface sites with As on iron (hydr)oxides and facilitate the As release [19]; (5) Diverse DOM could regulate the ecological niches of various microbial compositions, resulting in the redox zonation that subsequently affects the spatial distribution of As in aquifer systems [20]. Numerous studies have recently emphasized the significant functions of DOM in facilitating arsenic mobilization in aquifer systems from the central Yangtze River Basin [21], Yellow River Basin [22,23], and Pearl River Delta [24].…”